Huang Kuan, Cai Da-Niu, Chen Yong-Le, Wu You-Ting, Hu Xing-Bang, Zhang Zhi-Bing
School of Chemistry and Chemical Engineering, Nanjing University, Separation Engineering Research Center, Key Laboratory of Mesoscopic Chemistry of MOE, Nanjing 210093 (P. R. China), Fax: (+86) 25-83593772.
Chempluschem. 2014 Feb;79(2):241-249. doi: 10.1002/cplu.201300365. Epub 2013 Dec 4.
Three dual Lewis base functionalized ionic liquids (DLB-ILs) tethered with both carboxyl and tertiary amine groups on their anions were designed for highly efficient and selective absorption of H S. It was found that the DLB-ILs could reversibly absorb 0.39-0.84 mol of H S per mole of IL at 1 bar and 60 °C, which is significantly higher than that of other ILs. On the contrary, the CO absorption in this class of DLB-ILs was shown to be quite limited relative to H S owing to the coupling effect of the two Lewis base groups. It is the dual Lewis base functionalization that enables the significantly high values calculated for the ideal absorption selectivity for H S/CO , that is, 13-26 at 1 bar and 29-70 at 0.1 bar (60 °C). The selectivity even goes up to >100 at low pressures and high temperatures. It was further illustrated from DFT calculations and spectroscopy studies that the cooperation interaction of carboxyl⋅⋅⋅H S⋅⋅⋅amine and the reduced binding with CO were the major contributions to the high H S absorption capacity and H S/CO selectivity.
设计了三种在阴离子上连接有羧基和叔胺基团的双路易斯碱功能化离子液体（DLB-ILs），用于高效选择性吸收H₂S。研究发现，在1 bar和60°C条件下，每摩尔DLB-ILs可可逆吸收0.39 - 0.84摩尔H₂S，这显著高于其他离子液体。相反，由于两个路易斯碱基团的耦合效应，这类DLB-ILs对CO₂的吸收相当有限。正是双路易斯碱功能化使得H₂S/CO₂的理想吸收选择性计算值显著较高，即在1 bar时为13 - 26，在0.1 bar（60°C）时为29 - 70。在低压和高温下，选择性甚至高达>100。密度泛函理论（DFT）计算和光谱研究进一步表明，羧基···H₂S···胺的协同相互作用以及与CO₂结合的减弱是高H₂S吸收容量和H₂S/CO₂选择性的主要贡献因素。
